This invention relates, generally, to a recessed rough-in box for a dryer vent, to vent assemblies for use in combination with dryer vent rough-in boxes and, more particularly, to dryer vent rough-in boxes and vent assemblies which are designed to work effectively in hollow walls framed with 2xc3x974 scantling lumber.
In 1833, only a year after the city of Chicago began to rise from the treeless glacial plain adjacent lake Michigan, a carpenter from Connecticut named Augustine Deodat Taylor contracted to build a large number of houses in that Illinois city. Taylor responded by building what had become known as balloon frame houses. The walls, ceilings and roofs of a balloon frame structure are constructed from interconnected scantling frames which are subsequently covered. Though Taylor is frequently credited with the invention of the balloon frame structure, it seems that the construction technique emerged over several decades as a popular hybrid of many diverse building methods. In the historic Mississippi River town of Ste. Genevieve, Mo., the French were constructing houses, which still stand, using building methods which were precursors of the balloon frame method. Typically, the French constructed houses with palisade walls-vertical wooden posts placed side by side on 16-inch centers, with a continuous plate nailed across the top. Apparently, the walls were built flat on the ground, then tilted up within trenches dug along the perimeter of the building. Eventually, this palisade construction was modified so that the posts were nailed onto timber sills resting on stone or brick foundations. When standard-size lumber is substituted for the posts, the process is very close to the balloon construction method.
Light-weight, wood-frame houses have become the standard in this country. Because they are quite resistant to destruction in earthquake-prone regions, they are being adopted in faraway places, such as Japan, where killer earthquakes are common.
One of the distinguishing characteristics of wood-frame buildings is that the walls are generally hollow. The hollow walls facilitate the invisible routing of electrical, telecommunications and security system wiring, as well as gas and water pipes. Structural lumber used for nearly all interior walls, and for some exterior walls is typically 2xc3x974 scantling having a generally rectangular cross section that measures about 3.8 cm by 8.9 cm (1.5 inches by 3.5 inches). The walls are typically covered with gypsum board sheets that are nailed or screwed to the framing material. For residential applications, the gypsum board sheets have a standard thickness of about 1.25 cm (xc2xd inch). For commercial applications, the thickness of the gypsum board is about 1.59 cm (⅝ inch). Thus, the depth of a standard hollow interior wall, as constructed within the United States, is either 10.15 cm (4.0 inches) or 10.5 cm (4xe2x85x9 inches).
Within the past twenty years, it has become customary to install the drain and the hot and cold water taps for a washing machine in a recessed box that is coupled to the drain. Not only is space saved for washer installation, but any leaks from the taps flow into the drain. Clothes dryer vent installations have, as a rule, been notoriously sloppy. Not only has it been customary to terminate the vent pipe flush with the back wall, many builders install dryer vent pipes in 2xc3x974 framed walls. As the width of a 2xc3x974 stud is actually 3xc2xd inches, 4-inch aluminum vent pipes are frequently compressed so that they are of oval cross section. The main problem with using a 4-inch vent pipe in a 2xc3x974 framed is that it must pass through the top plate of the wall. It is nearly impossible to neatly compress an aluminum vent pipe so that will pass through the top plate and still leave a portion of the plate on either side of the pipe. A further problem is the frequent necessity of running the vent pipe between floor joists or trusses. If the vent pipe has been compressed to pass through a 2xc3x974 top plate, there are no elbows available that will mate to a compressed 4-inch vent pipe and then, after the 90-degree bend, revert to 4-inch round pipe. These problems result in very sloppy installations of dryer vents in 2xc3x974 framed walls. If an 90-degree elbow is required after the vent passes through a top plate of the same size, the quality of the installation is typically even worse.
Several U.S. patents have been granted for dryer vent assemblies. A first example is U.S. Pat. No. 5,590,477 to Carfagno, which discloses a dryer venting assembly having upper and lower mating rectangular housings, each of which has a protruding cylindrical flange with an opening into the housing to provide for the intake or exhaust of dryer exhaust gases. The Carfagno device appears to have two drawbacks. Firstly, neither of the housings provides a recess into which an accordioned flexible dryer conduit may be stored so that the dryer appliance may be positioned flush with the rear wall. Secondly, as the 90-degree transitions are not smooth, they will act as lint traps and also hamper the use of a vent-duct clean-out snake, which requires smooth transitions at right-angle junctions. A second example is U.S. Pat. No. 5,476,183 to Harpenau, which discloses a rectangular rough-in box for a dryer vent. This box, while providing room for an accordioned flexible dryer conduit, does not adequately address the problems inherent in installing a dryer vent in a 2xc3x974 framed wall.
What is needed is an easily-installable, recessed rough-in box for terminating a clothes dryer vent, that will fit in hollow walls framed with either 2xc3x974 or 2xc3x976 scantling studs. Also needed is a set of vent pipes, for use in combination with the recessed box, that can fit within a 3xc2xd inch wide cavity and pass through a top plate of the same width, without eliminating nearly all of the material in the top plate, make a smooth 90-degree bend to level, and transition to a 4-inch round vent pipe.
The present invention answers the heretofore expressed needs for an improved dryer vent system. According, a several embodiments of a clothes dryer vent system are provided. The vent system is designed for use in hollow walls that are framed with scantling and covered with sheathing secured to the scantling, and that have a hollow interior space that is uniformly at least about 3xc2xd inches wide. The vent system includes a rough-in box for recessed mounting within such a hollow wall, the rough-in box having a substantially planar rear panel, side panels and nonparallel top and bottom panels. The side, top and bottom panels intersect and are unitary with the rear panel, with each side panel intersecting and unitary with both top and bottom panels. The rough-in box also has a depth no greater than about 4 inches, and a stub connector pipe affixed within said top panel, the stub connector pipe having a lower portion of oval-shaped cross section within the box that is couplable to a flexible dryer vent hose and an upper portion outside the box directly couplable to an oblong vent pipe having a minor cross-sectional dimension no greater than about 2 inches. The top panel of the rough-in box incorporates a stub A vent pipe so dimensioned has a cross sectional area of about 13 square inches, which is xc2xd square inch more than that of a 4-inch diameter vent pipe. Because the Uniform Building Code requires that vent pipe sections which are hidden in wall spaces be metal, this embodiment employs a metal vent pipe stub which transitions from an oval, designed to couple to a standard 4-inch flexible vent duct, to a 2-inchxc3x977-inch connector. Also included in the vent system is at least one section of oblong vent pipe interconnected between the rough-in box and an exterior vent.
Several embodiments of the improved recessed rough-in box are provided, each of which has the attributes set forth above. The first embodiment thereof is designed for mounting between two parallel studs, and includes trimable support struts, each of which can be nailed to an adjacent stud. The first embodiment rough-in box also includes a vent stub connector pipe which passes through the top panel, the vent stub connector pipe having a lower oval configuration to fit a standard 4-inch diameter flexible vent hose that transitions outside the box to a low-profile 2-inchxc3x977-inch connector. The low profile connector is a metal insert which is inserted within the oval portion of the vent stub connector pipe in order to provide compliance with the Uniform Building Code that requires that any dryer vent run outside the box must be either metal or metal lined. The first embodiment rough-in box is also equipped with a trim piece which mates with the box, and which conceals the rough edges of abutting gypsum board.
A second embodiment of the rough-in box is equipped with adjustable telescoping brackets so that the box may be easily installed between two parallel studs that are positioned at least 16 inches between centers. The telescoping brackets are equipped with a cleat at each end thereof. Like the first embodiment, the second embodiment rough-in box is also equipped with a trim piece which mates with the box, and which conceals the rough edges of abutting gypsum board. In order to provide clearance for the telescoping brackets, a metal stub vent pipe having a transition from an oval configuration to a low-profile 2-inchxc3x977-inch configuration inside the box is used. The low-profile configuration continues as it passes through the top panel of the box, thereby providing a low-profile connector outside the box.
A third embodiment rough-in box is adapted for remodel construction. It incorporates multiple pop-up fasteners which enable the box to be inserted into a rectangular opening cut in gypsum board wall sheathing and secured within the opening. The third embodiment rough-in box has a built in trim flange, which conceals the rough edges of the rectangular opening in the sheathing. The stub vent pipe used for the third embodiment rough-in box is, preferably, identical to that used for the first embodiment box.
A fourth embodiment rough-in box is specifically designed for mounting between two adjacent framing studs positioned 16 inches between centers. As the box is slightly less than 14xc2xd inches wide, it may be attached directly to each of the adjacent studs. This embodiment also includes a removable trim piece.
A fifth embodiment rough-in box is similar to the fourth embodiment box, but has a metal vent pipe connector that transitions from an oval shape within the box to a 2-inchxc3x977-inch vent pipe having semi-tubular end walls outside the box.
The first four embodiments are designed such that the basic box unit of each, including a lower portion of the stub vent pipe, may be manufactured as a single injection molded piece of polymeric plastic material. In order to ensure compliance with the Uniform Building Code, the stub vent pipe must be lined with sheet metal once it is outside the box.
Also included with the present invention is a set of vent pipes designed for use in either 2xc3x974 or 2xc3x976 framed walls. The pipe vent pipe is preferably of generally rectangular cross section with dimensions of 2 inches by 6 inches. A special elbow is designed to pass through a 2xc3x974 top plate and still leave xc2xe inch of material on either side of the pipe. The elbow transitions into a 4-inch round pipe for routing through floor joists to a termination external to the structure.